Nuts usually have a closed internal thread, thereby being screwable onto the end of an external thread. The external thread is formed, for example, by a threaded stud, by the shaft of a screw, by a threaded spindle or a threaded rod. In some cases it is difficult or impossible to screw a nut onto an external thread from the free end. For this reason, nuts having parts that can be slid onto an external thread in a radial direction have been proposed for a long time.
In the year 1921, U.S. Pat. No. 1,375,781 already proposed to slide a one-piece nut having half an internal thread onto a threaded stud in the radial direction. A similar one-piece nut is known from DE 39 22 957 C1. A similar nut is also to be derived from German Utility Model DE 71 46 313, in which the opening of the threaded section is slightly smaller than the diameter of the external thread, resulting in a certain amount of elastic bending of the nut when pushed onto the external thread.
Two-piece nuts are known from U.S. Pat. No. 4,556,352, for example. The two nut parts have cooperating catch projections securing the nut parts in the use position, in which the internal thread surrounds the external thread with a small clearance. In addition, locking pins are also provided, joining the nut parts together in a positive manner. The manufacture and handling of these nuts, in particular the attachment of the locking pins, are complex.
U.S. Pat. No. 6,821,070 B1 describes a nut having two parts pivotable relative to one another, each having half of an internal thread. The pivoting takes place about a pivot axis running parallel to the axis of the internal thread. A third part pivotable about this axis is provided and is additionally displaceable in the direction of the axis of the internal thread. When this is displaced, it engages behind a retaining projection on the first part, thereby blocking the pivoting movement. In this way, the second part having the internal thread section is secured in its use position. This design is also extremely complex to manufacture and handle.
U.S. Pat. No. 4,462,731 describes a nut made of two parts having internal thread sections onto which a rigid shell is pushed to secure these parts relative to one another. The shell also has two shell parts which cooperate with recesses of the parts having internal thread sections to achieve a positive connection. This arrangement is also complex to manufacture and complicated to handle.
U.S. Pat. No. 4,826,376 describes a two-part nut in which the parts are divided in a plane running radially to the axis of the internal thread. Furthermore, the parts are rotatable relative to one another. In a first rotational position, the openings connected to the internal thread sections of the parts are aligned with one another and the internal thread sections of the parts are situated directly one above the other. The parts may be pushed onto an external thread in this position. The parts may then be rotated 180° relative to one another, so that the internal thread sections and the openings in the two parts connected thereto are opposite one another. The external thread is then encircled from both sides in two different planes. This arrangement is also complicated to manufacture.
U.S. Pat. No. 4,078,470 describes a divided nut, which is divided along vertical planes into two supplementary halves, with intermediate surfaces being provided approximately in the middle of the height of the nut parts and extending along a flat plane at an acute angle to the horizontal to create a locking effect to prevent a direct horizontal separation. To separate the nut parts, they may be displaced in only one direction parallel to the plane of the intermediate surfaces. However, the problem here is that there is a force component acting radially to the thread due to the slope of the thread flanks in tightening the nut parts. This force component presses the two nut parts radially away from one another. The radial movement of the nut parts is not avoided completely but instead is only deflected into a movement at an inclination along the plane of the intermediate surfaces. There is the risk that the force acting radially outward created by the external thread might overcome the resistance due to the inclined position of the intermediate surfaces. For this reason, U.S. Pat. No. 4,078,470 proposes the use of securing elements such as a securing ring or a securing splint to prevent the nut parts from moving apart from one another radially. This arrangement is either insecure because the nut parts may become loose or is complicated and complex to handle due to the manufacture of the additional securing elements.
U.S. Pat. No. 2,257,327 describes a nut whose nut parts are articulated so they are pivotable relative to one another about a threaded stud (hinge pin 11), which extends on each side of the thread or above the thread. The hinge pin limits the mobility of the nut parts relative to one another and prevents the nut parts from being able to become completely detached from one another.
DE-A-1 144 542 describes a nut having the features of the preamble of Patent claim 1. Two nut parts are divided in a parting plane running in the direction of the axis of the thread. At least one part has at least one projection, which is insertable into a recess in the other nut part. The projections and the corresponding recesses in the nut parts are designed in the form of an arc of a circle, so that the nut parts are guided in a rotational movement about an axis of rotation running across the axis of the internal thread when the circular projection is pushed into the circular recess. These nut parts are difficult to manufacture because the recesses and projections have several undercuts. Furthermore, they are difficult to handle because the recesses and projections must be aligned accurately with one another to join them. Finally, the projections and the walls of the recesses cooperating with the shoulders have only a very small material thickness and consequently have a low strength.
Accordingly, it would be desirable to create a nut of the type defined in the introduction which is simple to manufacture and to handle.